Golang : [json: cannot unmarshal object into Go value of type]



Tags : golang json-cannot-unmarshal-object

Un-marshalling JSON data from external sources can be challenging sometimes. Encountered this error message while working on the previous tutorial to display list of countries and the ISO2 codes.

json: cannot unmarshal object into Go value of type

Apparently, it was because the JSON data given by country.io has no fields identifiers. Only iso codes follow by country names. For instance :

{"BD": "Bangladesh", "BE": "Belgium" }

To deal(un-marshal) with this kind of data. First, we need to define a map expecting string and with the help of interface{}

For example,

 resp, err := http.Get("http://country.io/names.json")

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }

 defer resp.Body.Close()

 jsonCountriesData, err := ioutil.ReadAll(resp.Body)

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }

 countriesMap := make(map[string]interface{})
 // Decode JSON into our map
 err = json.Unmarshal([]byte(jsonCountriesData), &countriesMap)

 if err != nil {
 println(err)
 return
 }

See for full source code example at : https://www.socketloop.com/tutorials/golang-display-list-of-countries-and-iso-codes



Tags : golang json-cannot-unmarshal-object

By Adam Ng

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